Manufacture of commutator-bars.



l. BIGGERSTAFF.

MANUFACTURE OF COMMUTATOR BARS.

APPLICATION FILED NOV. 1. I914.

1,242,417. Patented Oct. 9,1917.

WITNESSES:

Ma @/w UNITED STATES PATENT OFFICE.

JAMES BIGGEBSTA FF, 0F Y ONKERS, NEW YORK, ASSIGNOR T0 OTIS ELEVATOR GOM- PANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

MANUFACTURE OF COMMUTATOB -IBABB.

Patented Oct. 9, 1917.

Application filed November 7, 19M. Serial No. 870,982.

To all whom it may concern:

Be it known that 1, JAMES BIGGERSTAFF,

a citizen of the United States, residing in pints, to take precautionary measures to.

prevent oxidation of the slots in the commutator cups into which the leads from the armature coils are soldered. Thus it has been a common practice to use a heated soldering iron b means of which. the slots are coated wit solder, this process in shop terms ordinarily being called tinning.

There are objections both to the use of solder as a coat as well as to the method itself, the main 0 jections to the latter being due to the fact that it is a laborious operation and involves a great expenditure in gas for heatin and repair of the soldering irons. A rther objection to the method, resides in the quite frequent burning of the cups due to an overheated iron, resu1ting,'upon attem t being made to solder the commutator leads into such cups, in a poorly soldered joint which seriously afiects the performance of the motor.

Now as to the objection to the use of solder as a coating, it is found that unless a workman exercises great skill and care, he is apt to apply the layers of solder a trifle too thick, thus preventing the armature leads which have been rolled to certain size from fitting the commutator cups, and causing a considerable amount of extra labor in making the on s of proper dimensions to receive the lee s.

It is the aim of my im roved method to overcome these objections. 1e features, and with the aid of the accompanyin drawings comprising Figures 1 and 2 whic illustrate a well known cm of commutator bar having a slotted cup, I will proceed with a description ofthe same.

The commutator bars such as 1, for example, are first assembled, and the cups 2 are then milled to form a slot 3 therein, the slots as is well known receiving a lead or leads from the armature coils which leads are soldered in the said slots. Now directly after the slots are milled, they are painted with a solution of liquid resin, the resin being cut with gasolene. As the gasolene evaporates the resin hardens, and'in this manner there is formed in each slot, :1 thin layer of resin which efi'ectually prevents the slots from becoming oxidized for an indefinite period of time. Any other well known 'nonacid constituents in the form of a flux dissolved in a volatile fluid may be used with equal, success as those above stated.

The leads of the armature may now be ositioned in the slots and soldered therein in the usual manner, it being particularly noted that in the soldering operation, the resin lining already formed in the slots, will in function, now serve as a soldering flux.

Now by comparing the new method with the old, involving the tinning process, it will be seen that the former involves a much simpler o oration, which of course means a saving o labor, and furthermore there is an additional saving in the elimination of the heated irons and solder and waste of solder, that is, as necessitated by the old method for tinning.

Further advantages of the new method reside in the elimination of the objectionable burning of the commutator bars, and also in the assurance that the slots in the on s will be of certain dimensions.

aving thus described my new and improved method, what I claim and desire to secure by Letters Patent of the United States is 1. In the art of manufacturing commutator bars, the process which consists in first assembling the commutator bars, then cutting the terminal slots therein and coatng the latter with a soldering flux in solution, while the are still bright.

2. In the art of manufacturng commutator bars, the process which consists in first assembling the commutator bars, then cuttin the terminal slots therein and coating the atter with a soldering flux dissolved with a volatile fluid, while the are still bright.

8. In the art of man acturinz commutator bars, the process which consists in first assembling the commutator bars, then cutting the terminal slots therein and coating the latter with a soldering flux dissolved in gasolenerwhile they are still bright.

4. In the art of manufacturing commutator bars, the process which consists in first assembling the commutator bars, then out ting the terminal slots therein and coating the latter with resin dissolved in gasolene, while the are still bright.

5. In t e art of manufacturing commutator bars, the process which consists in first assembling the commutator bars, then cutting terminal slots therein and coating the latter with resin in liquid form, while they are still bright.

6. In the art ofmanufacturing commutator bars, the process which consists in first assemblin the commutator bars, then cutting terminal slots therein and coatin the latter with a soldering flux in liquid orm, while they are still bri ht.

In testimony whereo I have signed my name to this specification in the presence of two subscrib'm witnesses.

AMES BIGGERSTAFF.

Witnesses:

EARL Bmonnsrm, JULrUs ANDERSON. 

